Damn it, how routine maintenance can spiral out of control

So I decided to check & adjust the valve clearance & check the spark plugs. Normally an easy task, taking maybe 40 minutes to an hour if you do it slow like me. Unfortunately upon screwing back the left valve cover, I misread the torque value as 15Nm (Head fixing screws) instead of 8Nm (Head cover fixing screws), so one one the bolts snapped. It snapped about 3mm deep into the fixing point as well, so no protruding end to grab onto. I can really hit myself atm, so stupid.

So now I have to buy some sort of extractor, a new bolt, etc. so won't be riding this weekend. Damn it.

So, any tips how to get the broken part out? The bolt is rather soft galvanized steel I think, so it shouldn't be super hard to get it out? Also maybe a good opportunity to replace these bolts with some better quality RVS or something. Does anyone happen to know a recommended vendor of those? Are there even any nice alternative valve cover bolts for our GRiSO?


This is how my sparkplugs looked like btw, after about 10.000km. Does this look too lean to you guys?

Left side plug:
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Right side plug:
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Hmm. Left looks like it could use a wee bit more. Have you adjusted the CO trim?

Never torque the valve cover screws. They just need a firm hand tightening.

beetle wrote:

Hmm. Left looks like it could use a wee bit more. Have you adjusted the CO trim?

No I haven't. How much trim would you advise?

Quote :

Never torque the valve cover screws. They just need a firm hand tightening.

Lesson learned. Ordered a 4mm left rotating drill, hopefully that will get it out as I doubt it will be very tight. If I screw that up it will become more complicated.
Thankfully the valve cover is not directly screwed onto the cylinder but on the rocker arm support.

Try +3 for starters. Check plugs again after a few hundred km.

Save that torque wrench for critical items such as head bolts. The majority are better done by hand.

motor-timothy wrote:

beetle wrote:

Hmm. Left looks like it could use a wee bit more. Have you adjusted the CO trim?

No I haven't. How much trim would you advise?

Quote :

Never torque the valve cover screws. They just need a firm hand tightening.

Lesson learned. Ordered a 4mm left rotating drill, hopefully that will get it out as I doubt it will be very tight. If I screw that up it will become more complicated.
Thankfully the valve cover is not directly screwed onto the cylinder but on the valve housing.

Good luck with the extraction. Have you tried to rotate the broken bit with a small screwdriver or similar.
If you need to drill dont forget to mask the area to prevent swarf falling into the oily bits.

eeyore wrote:

motor-timothy wrote:

beetle wrote:

Hmm. Left looks like it could use a wee bit more. Have you adjusted the CO trim?

No I haven't. How much trim would you advise?

Quote :

Never torque the valve cover screws. They just need a firm hand tightening.

Lesson learned. Ordered a 4mm left rotating drill, hopefully that will get it out as I doubt it will be very tight. If I screw that up it will become more complicated.
Thankfully the valve cover is not directly screwed onto the cylinder but on the valve housing.

Good luck with the extraction. Have you tried to rotate the broken bit with a small screwdriver or similar.
If you need to drill dont forget to mask the area to prevent swarf falling into the oily bits.

I'm considering removing the rocker arm support before drilling. I got a tip to use superglue on a screwdriver to help it grab onto the bolt remnant, so I'll try that tomorrow. Drilling will be last resort obviously.

Well nothing worked so I had to wait till the left rotating drill bit arrived. Thankfully that did the trick and I managed to get the broken stem out today without damaging the threads in the rocker cover.
I also ordered 8 new valve cover bolts at TLM as I have little faith in the integrity of the old ones, why on earth are these things like 5€ each, pure extortion. At least they look nice again and not like some bird vomited on them.
All in all a mistake that cost me around 50€ and a week of not riding my GRiSO (I had to take the train, such horror), but it could have been worse.

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Also put in Beetle's updated map & redid the throttle balance which was no longer so equal at 4.000RPM, then put the CO trim to +3, hopefully that helps it running less lean. All in all a productive GRiSO day.